High School

Given the function [tex]f(x) = 4|x - 5| + 3[/tex], for what values of [tex]x[/tex] is [tex]f(x) = 15[/tex]?

A. [tex]x = 2, x = 8[/tex]
B. [tex]x = 1.5, x = 8[/tex]
C. [tex]x = 2, x = 7.5[/tex]
D. [tex]x = 0.5, x = 7.5[/tex]

Answer :

Let's solve the problem step by step to find the values of [tex]\(x\)[/tex] for which [tex]\(f(x) = 15\)[/tex] given the function [tex]\(f(x) = 4|x - 5| + 3\)[/tex].

1. Set the function equal to 15:

[tex]\[
4|x - 5| + 3 = 15
\][/tex]

2. Isolate the absolute value:

Subtract 3 from both sides:

[tex]\[
4|x - 5| = 12
\][/tex]

3. Divide both sides by 4 to solve for the absolute value:

[tex]\[
|x - 5| = 3
\][/tex]

4. Consider the two cases for the absolute value equation:

Case 1: [tex]\(x - 5 = 3\)[/tex]

- Solve for [tex]\(x\)[/tex]:

[tex]\[
x = 3 + 5 = 8
\][/tex]

Case 2: [tex]\(x - 5 = -3\)[/tex]

- Solve for [tex]\(x\)[/tex]:

[tex]\[
x = -3 + 5 = 2
\][/tex]

5. Conclusion:

The values of [tex]\(x\)[/tex] for which [tex]\(f(x) = 15\)[/tex] are [tex]\(x = 8\)[/tex] and [tex]\(x = 2\)[/tex].

Therefore, the correct answer is [tex]\(x = 2\)[/tex] and [tex]\(x = 8\)[/tex].